Coupling compounds for color forming development



Patented Jan. 9, 1940 COUPLING COMPOUNDS FOR COLOR FORIVIING DEVELOPBIENT Wilhelm Schneider and Hans Loleit, Dessau, Germany, assignors, by mesne assignments, to

Agfa ldnsco Corporation, Binghamton, N. 32., a corporation of Delaware No Drawing. Application June 24, 1938, Serial No. 215,586. In- Germany July 3, 1937 12 Claims.

The present invention relates to coupling compounds for color forming development.

In the process of producing photographic color pictures by the operation known as color forming development there are used developers or photographic layers containing dyestuff components which yield with the products of the oxidation of the developer a colored picture at those parts of the layer where silver has been produced. Dyestufl components which have been recommended for the purpose are phenols, naphthols, aniline, naphthylamines, amino-naphthols, and compounds having an active methylene-group, therefore compounds which contain the radical with atom grouping:

It is an object of the present invention to provide an improvement in the process of producing photographic color pictures by color forming development.

A. further object of the invention resides in the provision of a new and improved class of dyestufi components, color formers or coupling compounds.

Still another object of the invention is the provision of photographic developers capable of color forming development comprising compounds from the new class of color formers.

A further object is to provide a photographic emulsion for color forming development having incorporated compounds from the new class of color formers being fast to difiusion with respect to the silver halide emulsions.

Further objects of the invention will appear from the detailed specification following-hereinalter.

We have found that an improvement in the process or producing photographic color pictures by color Xorrning development may be obtained by employing as the color forming compounds capable of forming a dyestufi with the oxidation product of an aromatic amino developer, a quaternary salt of a heterocyclic base having a reactlve methyl group. Suitable compounds are those oi the general formula in which R1 and Ba stand for hydrogen, inorganic or organic radicals, for example Cl, Br, I, $0335,

to the color developers.

or alkyl-, alkoxy-, aryl-, aralkyl-, aminoor substituted amino-groups, or

R1 and R2 together indicate a ring system, for

example a benzene ring, a naphthalene ring or-a more complex ring, which ring may contain substituents;

Rs stands for alkyl, aralkyl or aryl;

Y stands for CH=CH, S, Se, 0,

I (R4 and R5 represent alkyl, aryl or aralkyl) when Y=-CH=CH'-, the hydrogen atom in 4-position may be exchanged for CH3 or the hydrogen atoms in 3- and 4-positions 'may be exchanged for any substituents;

X stands for Cl, Br, 1, $04K, SO4CH2, 50402115, CIhCcH-sSOa or any other acid radical.

' Suitable quaternary salts of heterocyclic bases are, for example, the salts of picoline, lutidine, quinaldine,' i methylquinoline, ZA-dimethylquinoline, Z-methylthiazole; 2-methyl-benzthiazole, 2.3.3-trimethyi-indolenine, and salts of these bases containing various sulostituents. The picclines and Z-methylthiezole yield in the development with para-dimethylamino-eniline a red picture. The bases having condensed aromatic nuclei yield a blue picture. Compounds in which a. hydrogen atom of the active methyl-group is exchanged for another radical may also be used.

The dyestufi coupling components may be used both as an addition to the color developer and also to the emulsions. Since the salts of the aforesaid heterocylic bases are easily soluble in water, no difliculty is experienced in adding them With color developers which contain the aforesaid substances the. following colors are produced: with plcoline-ethyliodide, with ethyl-picoline-para-toluene sulfonote, with 2.4-dimethylthiazole-dimethyl sulfate V and ethyl-2.4-dimethylthiazole-para-toluene sulionate a red picture; with quinaldine-dimethyl sulfate, with 2.4-dlmethyl-quinoline-dimethyl sulfate, with e-naphthoquinalrline-dimethyl sul fate, with 2-methyl-benzthiazole-dimethyl sulfate and 12.3.3.5 penta methylindolenine-linstance, substantive groups as described in U. 8. Patents 2,179,238 and 2,178,612 aliphatic radicals consisting of an extended saturated or unsaturated carbon chain as described in U. S. patent application Ser. No. 94,340 filed August 5, 1936, said carbon chains preferably containing radicals which impart to the finished compounds solubility in water, and further other radicals of comparatively high molecular weight, which owing to their molecular dimensions prevent diffusion of the dyestui! components within the layers or from one layer to the other, such as for instance polypeptide radicals (U. S. Patent 2,179,244), radicals of carbohydrates (U. S. patent application Ser. No. 159,518 filed August 17, 1937), radicals of natural resins (U. S. patent application Ser. No. 164,499 filed September 18, 1937), sterol radicals (U. S. patent application Ser. No. 166,832 filed October 1, 1937). Furthermore there may be used compounds in which the radical of the dyestufi component itself recurs periodically (U. S. patent application Ser. No. 171,701 filed October 29, 1937). Furthermore radicals may be introduced into the molecule of the dyestuif components which make the latter fast to diffusion, which radicals consist of hydroaromatic and hydro-heterocyclic residues, then further menthane radicals (U. S. patent application Ser. No. 176,058 filed November 23, 1937).

Such groups may be introduced into the molecule of the dyestuff component by reaction with an aminoor carboxyl-group existing in the nucleus, an acid amide being formed. Alternatively, such groups may be linked directly with the nucleus or united in the form of a salt with the nitrogen of the heterocylic nucleus. Dyestuif components with groups fast to diffusion are, for example, quinaldine-N-dodecyl chloride, 6-stearyl-amino-2-methyl-benzthiazole-dirnethyl sulfate, bis-2-methylbenzthiazole-dimethyl sulfate of the formula rho-(L -om L CHs CH: 0 olso 0 colour If the last named color formers are added in the usual proportion to photographic emulsions, there is obtained on development with para-dimethyl-amino-a'niline a blue picture.

It is to be understood that the above named dyestuii components fast to diifusion are merely cited by way of example and that we do not intend to limit the scope of our invention to the specific details set forth.

The silver halide emulsions having dyestufi formers fast to diifusion may be made into photographic layers in the usual manner, one or more layers being on one. or both sides of the carrier superimposed if necessary.

The layers may be used for taking black-andwhite or color pictures. For the purposes of color photography several layers are with advantage sensitized for diiferent spectral regions. If desired, several color components may be introduced into one layer and these may be so selected that on development a neutral grey picture is produced.

However, the emulsions may be used in another manner, for example diflerently sensitized emulsions having diiferent color formers may be distributed in the form of line particles on a carrier.

The color picture may be produced in various ways, for example by the methods described in U. 8. Patents 2,179,228, 2,179,238 and 2,178,612 and U. S. patent applications Ser. No. 94,340 filed August 5, 1936, and Ser. No. 141,093 filed May 6, 1937. Again the components located in multilayer film may be converted into azo-dyes following development and fixing by treatment with a diazo compound such as a carbonic acid solution of tetrazotized benzidine disulfonic acid. There is thus produced in each emulsion layer together with a silver picture a dyestuii in which no structure can be perceived by magnification. The film is then treated with silver bleaching out bath, 1. e. that described in British Patent 401,340 to produce the dye image- I In the exposed emulsion layer the picture may be produced by simple color forming development or by reversal development as described in U. S.

Patent 2,179,234. Or the picture may be prc-' duced in multi-layer material, each layer containing one of said dyestufl components, by exposing the material, developing to black and white, in for instance amidol, dissolving silver from the negative so produced by bleaching in for example a chromic acid bath, forming images in the remaining silver halide, developing in a developer such as is used above, forming silver halide images by treatment in a bleaching bath,

1. e., again of chromic acid, forming latent images I pictures by color forming development, the improvement which comprises developing a lightsensitive silver halide emulsion in an amino developer while causing as the color forming compound a quaternary salt of a heterocyclic base having at least one heterocyclic nucleus, said nucleus containing only one nitrogen atom and besides a methyl group linked to the carbon atom at ortho-position to said nitrogen atom to react with the oxidation products of said amino developer to form a dyestuff image.

2. In a process of producing photographic color pictures by color forming development, the improvement which comprises developing an exposed photographic silver halide emulsion with an aromatic amino developer containing as the color forming compound a quaternary salt of a heterocyciic base having at least one heterocyclic nucleus, said nucleus containing only one nitrogen atom and besides a methyl group linked to the carbon atom at ortho-position to said nitrogen atom.

3. In a process of producing photographic color pictures by color forming development, the improvement which comprises exposing a photographic silver halide emulsion containing as the color forming compound a quaternary salt of a heterocyclic base having at least one heterocyclic nucleus, said nucleus containing only one nitrogen atom and besides a methyl group linked to the carbon atom at ortho-position to said nitrogen atom and developing said emulsion with an amazes aromatic amino developer to produce a silver and dyestuff image.

4. In a process of producing photographic color pictures by colorforming development, the improvement which comprises exposing a photographic silver halide emulsion containing as the color forming compound a quaternary salt of a heterocyclic base having at least one heterocyclic nucleus, said nucleus containing only one nitrogen atom and besides a methyl group linked to thecarbon atom at ortho-position to said nitrogen atom, said quaternary salt containing a radical imparting thereto fastness to diflusion with respect to the binding agent of said emulsion while retaining its solubility in aqueous liquids and developing said emulsion with an aromatic amino developer.

5. Silver halide emulsion for color photography containing a quaternary salt of a heterocyclic base having at least one heterocyclic nucleus, said nucleus containing only one nitrogen atom and besides a methyl group linked to the carbon atom at ortho-position to said nitrogen atom, said quaternary salt containing a radical imparting thereto fastness to diffusion with respect to'the binding agent of said emulsion while retaining its solubility in aqueous liquids.

6. A color forming developer comprisingan aqueous solution containing an aromatic amino developing agent and a quaternary salt of a heterocyclic base having at least one heterocyclic nucleus, said .5, wherein said heterocyclic base is selected from the class consisting of pyridines, quinolines, thia= 9. The silver halide emulsion defined in claim 5, wherein said heterocyclic base is selected from the class consisting of pyridines, quinolines, thiazoles and indolenines and wherein said radicle imparting fastness to diffusion is an aliphatic carbon chain of at least 5 carbon atoms.

10. A silver halide gelatine emulsion for color photography containing as a color development component quinaldine-N-dodecyl-chloride.

11. A silver halide gelatine emulsion for color photography containing as a color forming development component fi-stearyl-amino-Z-methylbenzthiazole-dimethyl sulfate.

12. A silver halide gelatine emulsion for color photography containing as a color development component bis-2-methyl benzthiazole dimethyl sulfate.

WILHELM SCHNEIDER. HANS LOLEI'I.

i .10 zoles and indolenines. 

